The Titans have a better chance to upset them than the Steelers do at least. The Titans have the kind of D that can slow teams down and make games messy and close along with an offense that while they plan to minimize mistakes offers a high risk high reward option more than the Steelers IMO. IF they decide to stop being so conservative and role the dice they have a chance to upset a good team.
The Titans played 4 playoff teams. They went 1-3 beating only KC and losing to the Buff, NO and Hou but they were very much in all 4 games. Just FYI All 4 games oddly enough were at home but the Titans are built to travel well.
The Steelers have played 5 playoff teams. They went 0-5. Pats, Buf, Sea, SF and Balt. While all the games but the Pats were a 1 score game they didn't manage to close a single team, they came close though for what that's worth.
Personally If either team gets in the position to take a shot at Batimore I'd rather it be the Titans. The Steelers give me no confidence they can manage the last 5 and especially the last 2 minutes vs a good team. Not that the Titans give me much either.